People often think of and define objects teleologically. For instance, we might understand a hammer in terms of its purpose of driving in nails. Such teleological thinking also influences many further judgments, including of category membership, essence, causation, persistence, and mereology. But how should we understand teleological thinking in the first place? This paper addresses this question by separating two senses of teleological thinking: mere teleology (simply ascribing a telos to an object) and teleological explanation (thinking an object is actually (...) explained by its telos). Experiment 1 examined cases where an object was designed for one purpose but is now widely used for a different purpose, and found that teleology judgments and teleological explanation judgments are dissociable: Only an artifact’s original purpose could serve as an explanation, but its new purpose could also be its telos. Experiments 2-3 sought to break down these factors that were sufficient for mere teleology; three factors other than creator’s intentions influenced teleology judgments: present use, collective recognition, and success at a function. Finally, Experiment 4 identified one factor that did not affect mere teleology: structure-function fit. Implications for work on object teleology and interpretations of teleological reasoning more generally are discussed. (shrink)